Apparatus for and method of generating television signals



March 30, 1943.

c. F. MATTKE 2,315,291

APPARATUS FOR AND METHOD OF GENERATING, TELEVISION SIGNALS Filed Feb.27, 1941 7 Sheets-Sheet 1 INVENTOR CF MATT/(E ATTOQNEV March so, 1943.c. F. MATTKEA APPARATUS FOR AND METHOD OF GENERATING-TELEVISION SIGNALSE .2 m m m mm m m5 a & 7 ,Y

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A TORNEY March 30, 1943; Q E MATTKE 2,315,291

APPARATUS FOR AND METHOD OF GENERATING TELEVISION SIGNALS Filed Feb.2'7, 1941 7 Sheets-Sheet 5 F/GI5 A TORNE V lNVE/VTOR By C. F MATT/(Esscolvos March 30, 1943. c MATTKE 2,315,291

APPARATUS FOR AND METHOD OF'GENERATING TELEVISION SIGNALS Filed- Feb.27, 1941 7 Sh eetS-Shee t 4 IN V[ N TOR By CF MATT/(E March 30, 1943. cMATTKE 7 2,315,291

APPARATUS FOR AND METHOD OF GENERATING TELEVISION SIGNALS '7Sheets-Sheet 5 Filed Feb. 27, l941 FOCAL AREA OF LIMITING APERTURE J6FIG. 78

uvvmrm y Cf. MATT/(E ATTORNEY March 1943- c; F. MATTKE APPARATUS FOR ANDMETHOD OF GENERATING TELEVISION SIGNALS Filed Feb. 27, 1941 7Sheets-Sheet 6 INVENTOR 6. f. MATT/(E March 30, 1943.-. IC -F IMATTKEI-r 2,315,291

APPARATUS FOR AND METHOD'OF GEXIIERATINQ TELEVISION SIGNALS Filed F313.27, 1941. Sheets-Sheet 7 c. E MAW/r5 an I TORNEV Patented Mar. so, 19432,315,291 mans-ms FOR AND mnon or GENEB- ATING TELEVISIQN SIGNALSCharles F. Mattke, Jackson Heights, N. Y.,aasignor to Bell 'l'ele NewYork, N. Y.,

phone laboratories, Incorporated,

a corporation of New York Application February 21, 1941, Serial no.sacs-14 invention relates to signaling and partic ularly to a method ofand apparatus 'for scanning motion picture film for generatingtelevision signals.

.An object of the invention is to provide an improved apparatusfo'r'scanningmotion picture 'film for television transmission.

Another object is to provide an ode ray scanning device. In accordancewith improved cathare projected from the film at the same rate. However,in transmitting television images, in accordance with standards adopted,by Radio Manufacturers Association, a field of view is scanned at therate of 60 field scans 01. 220 lines each per second with the lines ofone field scan interlaced with the lines of the preceding and followingfield scans so that 30 complete frame scannings of 441 lines each takeplace in one second. Therefore, in scanning for television transmissiona motion picture film which is' moved continuously at the-rate of 24film frames per second, it is desirable to scan the odd film' frames,for example, twice and even frames three timesrso that there are fivefield scans of 220% lines each in "-9, second, that is, 60 field scansor 30 completerframe scannings of 441 lines each,

interlaced, per second.

In accordance with a preferred 'embodimentof the present invention shownand described herestandard' motion picture'- .-practice a motion picturefilm is exposed at the .rate of 24 film (frames .per second andpicturesimage dissector'tube shown and the film being showninapproximately corthe apparatus shown in for the purpose of illustration,a cathode ray image dissector tube of special construction is employedfor generating a television image current under control of lightprojected through a continuously moving -motion picture film upon thelight sensitive cathode of the image dissector. tube. The imagedissector tube is provided'with an'a-pertureplate having five spacedapertures therein (instead of a single aperture heretofore employed),the centers of the apertures lying on a line substantiallyvparal lel tothe direction 7 of vertical movement of the electron image which isfocussed in the plane of the aperture plate, 4

and substantially parallel to the direction of motion of the motionpicture film. The usual horizontal and vertical deflecting coils and theusual sourcesot current for energizing the deflecting coils are-providedbut, since the motion picture film, and therefore the image projectedupon the cathode o! the dissector tube, is moved continuously at aconstant rate, the amplitude of the current supplied to the verticaldeflecting coils is correspondingly reduced. In order that elecvidedinthe path of scams. moi. ire-1.2)

trons emitted irom the cathode of the image dissector tube may passthrough only one of" the five scanning apertures different apertures insuccession, there is prothe light beam for projecting images from thefilmupon the cathode of the image dissector tube, a rotating shutterdisc having five arcuate light transmitting slots therein. The movementof the film, the rotation oi the light intercepting shuttenand thedeflecting fields for controlling the deflection of the electronjmageare all maintained in synchronism so that the pictures recorded on thefilm are scanned at a desired rate diflerent from the rate of movementof the film.

The invention will now ence to the accompanying drawings in which Fig. 1is a diagrammatic view at a motion picture film scanning apparatus inaccordance with the present invention:

Fig. 2 is a view of the motion picture film andshutter disc as viewedfrom the cathode. ray in Fig. 1, the disc rect dimensional relationship;Fig. 3 is a diagrammatic view or a portion or in Fig. 1 including inplan view the electron multiplier of theimage dissector tube;

Fig. 4 is a view taken along the line 4-4 of s.3:and i Figs. 5 to 11,inclusive, are diagrams to which reference will bemade in connectionwith an ex planation of the operation of the apparatus shown inFlgs. 1m4. Referring now to the drawings, a modified motion picture projectorprojects the successive ima es recorded on a the'cathode of a cathoderay image dissector tube.

The motion picture film I0 is driven by synchronous motor ll, throughshafts l2 and I3, gearbox l4, and film sprocket IS. The motor II' issuch that the film is driven continuously at thev rate of 24 frames persecond.

I! is directed through condensing lens i8, through slotted rotatabledisc 30 having slots 3|, 8!, 83, it and 35 therein, through the openingin name aperture plate 36 and film l0 and thence through lens 31 whichfocusses an image or the subjectmatter recorded on film l0 :upon thecathode oi an image dissector tube comprising an evacuated g ass housing88 or sin stanti'aliy cylindrical shape at a time, and through bedescribed with refer-' motion picture film l0 upon Light from sourcevare focussed to form an from which extends a side tube 39 of smallerdiameter. Ignoring for the present the fact that the disc 30 interceptsa portion of the light beam,

it is seen that'the lens 31 projects an image of a picture recorded onthe film upon the cathode 42, the image on the cathode being invertedwith respect to the image recorded on the film, as

indicated by the arrows. The inner surface of the housing 38 has a mevtallic coating or anode 40in which is formed a aperture plate 44,multi-' film I and disc 30 are shown more nearly correctly.

Any suitable means may be employed for supplying deflecting currents ofsaw-toothed wave plier plates 45, collector grid 46 and anode 41.

An electromotive force is applied between c athode 42 and anode 40through leads 48 and 49 from a circuit comprising battery 50, thepositive terminal'of which is, grounded, and a network 5I made up ofvoltage dividing resistors 52 and condensers 53, as shown. Leads fromthe circuit 5I are connected to the electrodes of the electronmultiplier as shown for applying appropriate potentials thereto. Theelectrons emittedfrom cathode 42 due to the light activation thereofelectron image in the plane of the aperture plate 44 having therein fivesmall spaced apertures I, 2, 3, 4, and 5, the centers of which are inalignment with the centers of the somewhat larger apertures GI, 52, 63,54 and 65, respectively, in the shield 43 (see Figs. 3 and 4), theelectron image being focussed by means of an axial magnetic field set updue to the current from source III flowing through the coil II whichsurrounds the glass envelope 3B and :vlgich extends substantially thefull length of the There are provided two pairs of deflecting coils thehorizontal [or high frequency deflecting coils I2 and the vertical orlow frequency deflecting coils- 13. e magnetic field set up when thesedeflecting coilsare suitably energized cause the beam of electronsemitted from the cathode 42 and. therefore, the electron image focussedin the plane of the scanning apertures I to 5, inclusive, to bedeflected along both horizontal and vertical coordinates. The electronbeam reaching the apertured shield 43 s of such size that electrons canpass through only one of the apertures BI to 55, inclusive, at a timebut electrons can pass through different apertures in succession dueto.the action. of the rotating slotted disc 34 and to the deflection ofthe electron beam by the vertical deflecting field. The motion of theelectron image with respect to the scanning aver- 'tures results inprogressively selecting elemental areas of the image. Due to the,bombardment of the first of the plurality of multiplier plates by theelectrons from different portions of the cathode 42 in succession, animage,current is set upin' the circuit including lead "I4 connected tothe collector grid 46, the terminating impedform to the deflecting coilsI2 and I3. As shown diagrammatically in Fig. 1 the drawings, there areprovided a 26,460-cycle controlled oscillator I8 from which is derivedby successive steps the submultiple frequency sources 19 and I! of13,230-cycle and Gil-cycle waves, respectively, of generallysquare-topped wave form. The cycle wave from the power source I25 andthe GO-cycle wave from the submultiple frequency generator I! areimpressed upon the frequency control circuit I24. There is produced bythe circuit I24 as the result of beating together the waves from sourcesI25 and IT, a control current which is impressed upon the oscillator181'or maintaining the frequency of the wave produced cult which, inturn, controls the horizontal sweep circuit for supplying a toothedcurrent wave to the horizontal deflecting coils I2. An arrangement ofthe type described for generating waves for controlling the sweepcircuits which, in turn, control the deflection of a cathode ray-beamand for maintaining the waves in synchronism with an alternating currentpower source is disclosed in an article by A. Vs-Bedford and JohnPaulSmith on page 51 of -RCA Review for July 1940, pub- 13,230-cycle ,saw-

lished by RCA Institute Technical Press, 75,

Variclr': Street. New .York, New York. Sixty cycle pulses produced bythe generator 8| under controlgof the subharmonic generator I! controlth vertical sweep' circuit 82 which supplies a Gil-cycle saw-toothedcurrent cal deflecting coils I3.

In order that the electron image produced in the plane of theapertureplitte 44 may be brought into correct vertical and horizontalalignment, there are provided 1 batteries 83 and 84 is supplied throughto the horizontal and and I3, respectively.

from which direct current vertical deflecting coils I2 The operationofthe scanning system shown In I Fig. 1 may best be understood byreferring to Figs. 5 to 12, inclusive.

Referring to Fig. '5 the film I0 is moved downwardly, as viewed in thefigure, at the rate of 24 film frames per second, so that, at thebeginning of successive equal periods of ,4, second, the fllm is inpositions marked A, 13,

lower portion of the figure. Assuming for the ,anceelement 15 andground. This image current may be amplified by the vacuum tube amplifierI6 if desired, and transmitted over a suitable transmission medium suchas a balanced.

line 11. a y

In Fig. 1, the film Ill and disc 30, for example, are not shown in theircorrect relative dimensions. In. Fig. 2 the relative dimensions of theode 42 of the image dlssector tube, then the elec*- tron imagecorresponding to frame '1 formed in the plane of the aperture-plate 44would appear at I. Due to the downward ID from position A to position 3,the image formed on the cathode 42 and thereforethe electron imageformed in the plane aperture plate 44 Will move upwardly by acorresponding amount. that is, anamount corresponding to a filr:

wave to the verti-.

Potentiometers u and a? C, D, Eand F. spectively.- The time periodsareindicated at the saw-toothed wave This vertical motion of theelectron image is supplemental by deflecting the cathode beam to causethe electron image tomove through a distance corresponding to of a filmframe by applying to the vertical deflecting coils II a regular 90 fromsource '82. f the apertures I, 2, 3, l and in the aperture plate I l,one only is effective in the process of scanning the image during acertain field scanning period,-

the apertures becoming eifective successively during successive fieldscanning periods. In Fig. 5

the apertures are shown aligned on equally spaced horizontal lines whichare numbered at the left-hand side of the drawing. During the firstfield scanning period only aperture i is effective and during thisperiod the electron image of frame Ismoves verticallywith respect toaperture i through adistance corresponding to a film frame. While theelectron image is thus moved along a vertical component, it is alsomoved horizontally in the usual manner at the rate of 541 lines perframe scanning period of /30 second or 220 /2 lines per field scanningperiods of let second by applying a saw-toothed wave current from thehorizontal sweep circuit to the horizontal sweep coils I2.

At the start of the second field scanning pe-- riod, the film and theelectron image are in the positions shown at B in Fig. 5. Aperture 2 isnow effective and due to the continuous movement of the film l0 and thedeflection of-the electron beam from cathode 42, film frame I is scanneda second time. At the beginning of the third field scanning periodaperture 3 becomes effective in the process of scanning film frame 11.Aperture 4 next becomes effective in the scanning of film frame 11' asecond time during the fourth field scanning period and then aperture 5becomes effective in the process of scanning film frame II a third time.At the beginning of the sixth field scanning period, as shown by F inFig. 5, frame IIIoccupies the position whlch was occupied by frame I andelectron image 111 occupies the position which was occupied by electroniriiage I at the beginning of the first field scanning period A. Thus,alternate film frames are scanned twice and the remaining frames arescanned three times along 441 lines per frame scanning period. the lineson one field scanning being interlaced with those of the preceding orfollowing field scanning. The film moving con-' tinuously at 24 filmframes per second is thus scanned at the rate of 60 field scans persecond.

As will be apparent from a consideration of Figs. 2, 6; 10 and 11, theapertures l, 2, 8, 6 and 5 in the aperture plate 46 are made effectivefor scanning one at a time in succession by the rotating slotted disc30' which permits only a narrow strip of the film l0 tobe illuminated ata time the beam.

. aperture I iii and, therefore, an optical image 9| of this narrowstrip to be focussed upon the cathode 62 and.

an electron image 92 corresponding to this narrow strip to be focussedin the planeof the aperture plate 64. The position of film frames '1.and II of film it, as indicated in Fig. 6, corresponds to the conditiondepicted at A'of Fig. 5

and the relative positions of the disc 30 and film Iii are as shown inFig. 2.

At the commencement of scanning of film frame I, the leading'portion(lower portion, as

viewed in Fig.- 6) of film frame I is illuminated and the light beamfrom this portion of the film reaches position 9| on the light sensitivesurface of cathode 42, light from the first scanned line being at aboutthe central portion of The electron beam from portion ii of the cathodeis focussed upon the aperture plate 64 so that, as the electron beam isdeflected, elecof' frame-'1- "trons corresponding to the elemental areasof the first scanned line pass successively through in aperture plate44. It is apparent that if 'the of the light beam and of the electronbeam would be limited only by the opening in aperture plate 38 andelectrons would pass simultaneously through a plurality of apertures inaperture plate 66. The width of the slots in disc 30 is sulficientlynarrow that electrons emitted from cathode 42 can pass through only oneof the apertures in aperture plate M at a time. 7

During the first field scan of film frame I, the

lfihn moves downwardly, as viewed in Fig. 6, through a distance of frameand-the'slot Si in disc 30 in effect moves upwardly through a distanceof frame, that is, through a distance indicated by IA in Fig. 6. Duringthis period the light beam intercepted by cathode 42 moves from position9! downwardly through a distance indicated by IB in Fig. 6. Asaw-toothed wave deflecting field (Fig. l) is applied to the verticaldeflecting coils 13 so that, as the light beam impinging on cathode 62moves downwardly through a distance lB,.the positionof the electron beamat electrode at remains fixed with respect to the vertical coordinate,Thus electrons emitted from cathode 42 in response to light fromsuccessive elemental areas along successive lines of film frame I pass,in order,

through aperture l-in electrode 44 and impinge .upon the firstmultiplier electrode or target B5 of the electron multiplier 39 to setup a corresponding image current in the output circuit of themultiplier.

V In a similar manner, during the second field scan of frame I, the filmis illuminated by light passing through slot 3; in disc 30, the lightbeam leaving the film moves upwardly through a distance indicated at 2A,the light beam impingingon'the cathode '42 moves downwardly through adistance indicated at ZB'and electronsemitted from the cathode passthrough the aperture 2 in electrode 64, Similarly, film frame II isillumi nated three times during the next three field scanning periods,the light beam from the film being swept over the area indicated at 3Aduring the first field scan, over the area All during the second fieldscan,

the electrons emitted from the cathode pass through the scanningapertures 3. 4 and 5, re-

spectively, of-the aperture plate M.

'In accordance with the standards adopted by the Radio ManufacturersAssociation, there is an interval. about '7 percent of the fieldscanning period. at the end of each field scanning period during whichthe beam of the image producing cathode ray tube is" preferably reducedin intensity and is returned to its. initial scanning position. Duringthis interval, frame synchronizing impulses are transmitted and no imageproduction takes 1ace.- As may be seen from Fig. '7B, for example, thereis an interval between successive field scanning periods durin whichone'slot of disc 30 is moving out of alignment with. the opening in theaperture slotted disc 30 were omitted, the sizeand over the area 5Aduring the third field scan of frame II. During '80 at a, time abouthalf way between alignment with the opening in aperture plate 36. InFig. 7B, for example, slot 35 has just moved out of alignment with theopening in aperture plate 36 and slot-3| has moved. into position forscanning of thefirst line of film frame I during the first fieldscanning period. The length of each of the slots. 3| to 35 is preferablysuch with respect to the width of the opening in plate 36 that one slotcan move completely out of, and a succeeding slot can movecompletelyinto, alignment with the opening in plate 36 within the periodof about 7 per cent oi the field scanning period alotted to the verticalsynchronizing impulses.

Fig. 7A shows the position of the optical image at 9| and .the positionof the electron image at 92, as is shown in Fig. 6, picted in Fig. 7Band also at A of Fig. 5. In Fig. 7C is shown a saw-toothed electric wave30. as shown in the lower part of'Fig. 1, for energizing the verticaldeflecting coil 13. It will be noted that the zero point on thehorizontal time axis of Fig. 7C is in vertical alignment with thescanning aperture plate 44. This is intended to indicate that at thebeginning of the first field scanning. period of filmirame I thevertical deflecting saw-toothed wave is at its minimum amplitude.

Figs. 8A, 8B and 8C are similar to Figs. 7A, 7B and 70, respectively,but depict a condition encountered about ,420 second after the conditiondepicted in Figs. 7A, 7B and 70. As shown in Fig. 8B, at this time aboutthe central portion of fiim'frame I is being scanned. As shown in Fig.8A, and also in Fig. 6, the light beam is intercepted by the cathode 4-2at a lower position 93 as viewed in the figure. As shown'in Fig. zeroand V second, the amplitude of the vertical deflecting wave 90 is aboutone-hall. its maximum amplitude, this amplitude of the defiecting'wavecausing the electron beam to be deflected so as to for the conditionde-.

of each field scanning period during which the electron beam of theimage producing cathode ray tube is reduced in intensity and returned toits initial scanningposition. During this interval frame synchronizingimpulses are transmitted and no image production takes place. This 7 percent of the field scanningperiod is also required for the-return sweepof the cathode ray beam emitted from the cathode 42 or the imagedissector tube. In standard motion picture film the dimension along thelength of the film of the frame line between two successive pictureportions is about per cent of the length of an entire film frameconsisting of a'picture portion and a frame line. In order to. avoidwaste of transmission time, it is desirable to scan a picture portiononly of a film frame during 93 per cent of a field scanning period, thusallowing 7 per cent of the field scanning period between the time ofscanning the last scanned elemental area of one field scanning periodand the first scanned elemental area of the succeeding field scanningperiod. In order that the picture portion only of the motion picturefilm may be scanned during 93 per cent of the field scanning period 'ofonesixtieth second, the slots 3| to 36 in the disc 30 may be laid out sothat a picture portion of the film is.traversed by a slot in 93 per centof a field scanning period and the amplitude of the vertical deflectingcurrent from source 82 reduced so that the electron image correspondingto a picture portion only of the motion picture film is scanned in 93per cent of the field scanning period.

Thesubject-matter of this application is related to that of myapplication Serial No. 380,773, filed trode having a plurality of spacedapertures therereach position 92 on the aperture plate 44. Figs.

9A, 9B and 9C are similar to Figs. 8A, 8B and LC, respectively, butdepicit a condition encountered just prior to the end of the first fieldscanning of film frame I. As shown in Fig. 93 slot 3| is about to startmoving out of, and slot 32 about to start moving into, alignment withthe opening in plate 36. Fig. 9A shows that at this time the light beamis intercepted by the cathode 42 at a still lower position 94, which isalso shown in Fig. 6. The vertical sweep wave 90 is now at its maximumamplitude to cause the electron beam to be deflected to position 92 onthe aperture plate 44. 1

In a similar manner, during a difierent field scanning period when lightis directedthrough some other slot of disc 30, the light beam will beintercepted initially at some other position or cathode 42 such that theelectron beam will pass through a corresponding aperture in apertureplate 44 and, as the light beam illuminates ditierent portions ofcathode "in succession, the saw-toothed wave 96 impressed upon verticaldefiecting coils 13 will set up a beam deflecting-field to. cause theposition oi the electron image to, re-

per cent 01 the field scanningf period, at the-end 78 in through whichelectrons from said cathode may pass to reach said target, means fordirecting a light beam upon said cathode to illuminate in successiondifierent areas of said cathode which may overlap in part, each areabeing illuminated a small section at a time and diiierent sections insuccession by moving the light beam to cause electrons emitted from,different of said areas of said cathode to reach'diflerent apertures.respectively, in said electrode and means for deflecting the electronbeam to compensate in part. at least for the movement of said light beamso that electrons emitted from'any section 01' a certain area of saidcathode will pass through thecorresponding aperture in said electrode.

2. An image dlssector tube comprising a light sensitive cathode foremitting electrons 'inaccordancewith the illumination of elemental areasthereof, an anode, means for producing an electron image correspondingto an optical image focussed on said cathode, an electron multipliercomprising an aperture electrode having a plurality oi spaced scanningapertures therein subs'tantially in the plane of said electron image, ashielding electrode located between said aperture electrode and saidcathode and having therein a plurality of apertures in alignment withsaid scanning apertures respectively, a plurality of multiplierelectrodes, tion to be bombarded by electrons passing through saidscanning apertures, and means for deflecting the electron beam from saidcathode to move said .electron image with respect to said scanningapertures and to cause electrons from said cathode to the first of whichis in posi field ofview upon said cathode to 3. Scanning apparatuscomprising alight sensitive cathode for emitting electrons in accordancewith the illumination of elemental portions thereof,-means forilluminating portions of a field of view in succession, means fordirecting light from the successively illuminated portions of theilluminate portions thereof in succession, an aperture electrode havinga plurality of spaced scanning apertures therein through which electronsemitted irom said cathode may pass, means for focussing the electronsfrom said cathode in the plane of said aperture electrode, and means forcausing the electrons emitted from different elemental areas or saidcathode to pass in succession through one" oi saidscanning apertures andthrough different apertures during successive time interv 4. Apparatusfor scanning continuously moving motion picture film comprising acathode ray scanning device having a light sensitive cathode and anaperture electrode having a plurality of scanning apertures therein,means for projecting an optical image from said film to said cathtrol ofelectrons transmitted through said scanning apertures as the result ofthe scanning of the electron image by said apertures successively forproducing an image current ,which may be used for controlling theproduction of television images corresponding to the pictures recordedon said motion picture film.

6. Apparatus for scanning continuously moving motion picture film sothat each frame of the motion picture film is scanned a plurality oftimes comprising a light sensitive cathode and an aperture'electrodehavinga plurality of scanning apertures, therein, means for projectingan optical ode while said film is in motion, means for accelerating theelectrons emitted from said cathode to produce an electron beam, meansfor iocussing said electrons to produce substantially in the plane 01said aperture electrode an electron image corresponding to the opticalimage produced on said cathode, means for causing said scanningapertures one ata time in succession to scan the electron ima'ge formedin said plane, said means comp means for deflecting said electron beam,and means under control of electrons transmitted through said scanningapertures as the result-oi the scanning by said apertures successivelyof the electron image landed in said plane for producing an imagecurrent which may be used for controlling the production of televisionimages corresponding to the- -pictures recorded on said motion picturefilm.

5. Apparatus for scanning motion picture mm for television transmissioncomprising means for continuously moving the motion pictur film at imagefrom said film upon said cathode, means for accelerating the electronsemitted from saidcathode to produce an electron beam, means i'orfocussing said electrons to produce in the plane of said apertureelectrode an electron image corresponding to said optical image meansfor de fiectingsaid electron beam'in a direction substantiallyperpendicular to .the direction of motion or the film to cause elementalareas in succession oi the' electron image to be scanned, means fordeflecting the electron image in a direction substantially parallel tothe direction or to be scanned in a period 1688i than that in which asubstantially uniform rate, a cathode ray scanning device having a lightsensitive cathode, means tor'projecting an optical image from said filmto said cathode while said film is in motion means for accelerating theelectrons from said cathode to produce an electron beam, means forIocussing said electrons to produce in a certain plane an electron imagecorresponding to the opa frame of the film moves past a fixed point, thescanning apertures insaid electrode being'so positioned that an electronimage corresponding to a frame oi the motion picture film is completelyscanned at leasttwo times in succession bydflferentapertures,respectively, means for preventing electrons or said electron image fromreaching more than one or said plurality otvapertures at atime", andmeans under control of electrons transmitted through said scanningapertures as the result of the scanning of the electronimage by saidapertures successively i'orproducing image current which may be used forcontrolling the production of televisionimages. corresponding to thepictures recorded on said motion picture mm. A

- g CHARLES F. MA'ITKE.

tical image produced on said cathode, said oathode ray device comprisingan electrode substantially in said plane having a; plurality of electrontransmitting scanning apertures therein, means for deflecting saidelectron beam to cause a scan-.

